Presently, the types in head of windshield wiper arm are many in variety. Different type design of wiper arm head must be coordinated with its exclusive joint apparatus to enable securely joint each other. Such as USA issued patents U.S. Pat. Nos. 6,516,491, 6,687,948, 6,782,581, 6,836,927, 6,836,926 and U.S. Pat. No. 6,910,244 as well as USA published patents US2004/0025280, US2005/0039292, US2004/0098821 and US2004/0117938, all disclosed their different types of wiper arm head in association with its exclusive joint apparatus; In which, a conventional wiper arm disclosed in USA published patents US2004/0117938 is shown in the FIG. 1, FIG. 3 through FIG. 7. A fixing spindle 3 and a press curbing strip 4 are erected on one lateral side of the head 2 in parallel and front-and-rear juxtaposed manner; said press curbing strip 4 is formed by sidewise projecting the top surface of said head 2 horizontally, then bends its end to become a downwards curbing tongue 4a; said fixing spindle 3 is slightly lower than said press curbing strip 4 with adequate space. Refer to FIG. 2 to FIG. 6, the exclusively coordinated joint apparatus of said wiper arm 1 with said curbing head 2 comprises a main body 10 and a upper canopy 20; wherein, said main body 10 is a cuboid with a bulging hump 11 being raised in the center of its top surface, a spindle hole 12 is perforated through both sides of said bulging hump 11, a pair of parallel and symmetrical insetting clip 13 is inwards built at the bottom side of said main body 10, both of said insetting clip 13 and said spindle hole 12 are arranged in perpendicular manner; said upper canopy 20 is a rectangular cannulation with opening directly jacketing said main body 10 and with a round hole 21 perforated on one long lateral side, the center of said round hole 21 is superimposed with that of said spindle hole 12 on said main body 10.
The rigging assembly of said wiper arm 1 with said curbing head 2 and windshield wiper is shown in the FIG. 3 through FIG. 7, First, by means of said insetting clip 13, employ said main body 10 to clamp the central position in the elastic metal strip 7 of said wiper 6, then make said upper canopy 20 to jacket said main body 10 (as shown in A-A sectional view of the FIG. 7) so that all three elements of said upper canopy 20, said main body 10 and said wiper 6 are closely jointed together as a unitary body; Afterwards, first overturn said upper canopy 20 into vertical status and let its round hole 21 align with the center in said fixing spindle 3 of said wiper arm 1 (as shown in the FIG. 4), then insert said fixing spindle 3 into said round hole 21 of said upper canopy 20 due to the distance between said top surface 22 of said upper canopy 20 and said round hole 21 is less than that of said fixing spindle 3 on said curbing head 2 and said press curbing strip 4, said fixing spindle 3 can be smoothly inserted into said round hole 21 of said upper canopy 20 without any interference from said curbing tongue 4a at the end of said press curbing strip 4 up to the free end of said fixing spindle 3 passes through said spindle hole 12 on said main body 10 and adherent rest to the other inner wall of said upper canopy 20 (as shown in the FIG. 5); Lastly, overturn said upper canopy 20 again to resume back into its original horizontal status (as shown in the FIG. 6) such that said press curbing strip 4 and said curbing tongue 4a on the side of said curbing head 2 contact the top surface 22 of said upper canopy 20 and its other lateral side (as shown in the FIG. 7), thus said upper canopy 20 and said main body 10 are confined to said curbing tongue 4a at the end of said press curbing strip 4 so that said wiper 6 is unlikely to disjoint off said wiper arm 1.
However, during practical operation of replacing worn windshield wiper by new one, there are some drawbacks of aforementioned joint apparatus as below:
1. Refer to FIG. 8 and FIG. 9, for said wiper arm 1 with said curbing head 2:
during the replacement of new windshield wiper, an upwards force must be first applied on said wiper arm 1, which tightly stays with the windshield G in horizontal position (as shown in the FIG. 8); Exploit pivot of said elastic foldable articulation 5, said wiper arm 1 is folded in upright position to enable the wiper 6 depart away from windshield G (as shown in FIG. 9); Then, the dismantling procedure of said worn wiper 6 can be start to proceed; As described above, in order to let said upper canopy 20 get rid of the confinement by said curbing tongue 4a at the end of said press curbing strip 4, said integral wiper 6 must be overturned 90 degree angle such that being able to draw out of said fixing spindle 3; Said wiper 6 under such acting operation always hit the replacing operator during overturn of said wiper 6; More than that, said wiper 6 will unexpectedly re-bounce back to resume its original horizon status under inadvertently touch said curbing head 2 of said wiper arm 1 by hand due to any carelessness, thus serious drawback of hurt the windshield G will happen in accompanied consequence of said curbing head 2 directly strike the surface of said windshield G.
2. Refer to FIG. 4 and FIG. 5, before operation of rigging assembly or dismantling said wiper 6:
Said upper canopy 20 on said wiper 6 must always be overturned to perpendicular to said curbing head 2 each other under double confinement of said fixing spindle 3 on said curbing head 2 and said curbing tongue 4a on said press curbing strip 4 (as shown in the FIG. 5); Furthermore, other than said fixing spindle 3 must be alignment with said round hole 21 on said upper canopy 20, the applying force must keep parallel all the way during procedure of inserting of drawing out of said spindle hole 12 on said main body 10 (as shown in the FIG. 4), otherwise the difficulty of inserting of drawing will increases due to any unbalance; Therefore, the operation of rigging assembly or dismantling said wiper 6 seems difficult and time-wasting so that not being satisfied with the basic demand of simple and easy operation conversely, thus the structure of said main body 10 and said upper canopy 20 is definitely a bad contrivance.